The present invention relates to an arrangement of a shaft in a support.
It in particular applies to the arrangement of a shaft of an automobile vehicle steering column in a column body forming a support.
There is already known in the art, in particular from U.S. Pat. No. 4,979,834, an arrangement of a shaft in a support, of the type in which the shaft is rotatively mounted in the support by rolling bearing means comprising at least one first rolling bearing providing an oblique contact surface axially biased in one direction by an elastic return force, and in a direction opposed to the foregoing direction, by a sleeve forming a thrust block carried by the shaft, this block being axially movable between the first and second positions of application of a force opposed to that of the return force, the magnitude of this opposing force being greater in the second position of the block than in the first position of the latter.
In the case of an automobile vehicle steering column arranged in accordance with the teaching of the foregoing document, the column shaft is rotatively mounted in the column body, forming a support, by means of a lower rolling bearing and an upper rolling bearing providing an oblique contact surface mounted in opposed relation in the body.
The lower rolling bearing is subjected to the elastic return force which is transmitted to the upper rolling bearing through the column body. The thrust block permits axially clamping the upper rolling bearing by opposing the return force.
The column shaft is assembled with the column body prior to the mounting of this column in the vehicle. In its first position, the thrust block exerts on the upper rolling bearing a clamping force which is relatively limited but sufficient to guarantee the cohesion of the assembly during the steering column handling or transporting operations.
After the mounting of the steering column in the vehicle, the steering wheel is fixed on the upper end of the shaft in contact with the thrust block in such a manner as to displace the latter toward its second position. In this second position, the block exerts on the upper rolling bearing a large clamping force which guarantees a firm assembly of the steering column in the vehicle.
The two positions of the thrust block therefore permit axially clamping the upper rolling bearing in two stages before and after the mounting of this column in the vehicle.
In U.S. Pat. No. 4,979,834, the thrust block is connected to the shaft by the clipping or latching of an inner annular projection of the block in an outer annular groove of the shaft. The width of the groove is sufficient to permit the axial sliding of the thrust block between its two positions. In order to guarantee the irreversibility of the clipping connection, the rolling bearing cooperates with a wedging effect with a tapered end of the thrust block to prevent the projection provided on this block from disengaging from the groove.
The means for connecting the thrust block with the shaft described in U.S. Pat. No. 4,979,834 has in particular the drawback of requiring further work on the shaft to form the clipping groove, for example a machining operation. Further, this groove creates a weakened region of the shaft.